Rob Clark posted the Freedreno A3xx patch-set for implementing the XA acceleration architecture using the Gallium3D driver for 2D. Rob explains that -- at least for the Google Nexus 4 -- the newer Qualcomm Snapdragon devices no longer have a 2D graphics core. While he's implemented the Freedreno XA support, he's required breaking the current XA API, which now must undergo review from fellow XA stakeholders.
The XA state tracker for Gallium3D was developed by VMware for their virtual SVGA II graphics device, which is used by virtual machines on their virtualization platform. XA passes 2D commands to the 3D driver for rendering and is superior to the older Xorg state tracker.
The current Freedreno XA patches can be found on the Mesa mailing list.